Foot ulcers are an important complication of diabetes mellitus and often precede lower- extremity amputation. Insufficient perfusion of the tissues around ulcers may be the most limiting component to ulcer formation and healing. However, it is historically very difficult to assess distal leg and foot perfusion accurately. The objective of ths study is to evaluate a newly developed non-contrast MRI technique to characterize local skeletal muscle microcirculation in calf and foot. This will be performed in groups of patients with diabetes and foot ulcers, in comparison with healthy subjects and patients with peripheral vascular disease. The long term goal is to promote microcirculation as a prime evaluation target before embarking on interventional treatment for limb preservation in a patient with diabetes. Two specific aims will be addressed. Specific Aim 1 will compare the non-contrast MRI skeletal muscle perfusion and oxygenation techniques with clinical methods to assess perfusion of lower extremities. Specific Aim 2 will determine the relationships between regional skeletal muscle perfusion / oxygenation, and the presence of pedal ulcers in patients with diabetes. This will be compared with patients with peripheral vascular disease and foot ulcers, as well as with healthy volunteers. All study will be performed at rest and during a challenge exercise. It is hypothesized that these regional perfusion and oxygenation indices will be strongly associated with the severity of diabetes and presence of foot ulcer. The completion of this study will provide a foundation for further detailed understanding of the local wound perfusion, which is essential to developing a management plan and establishing prognosis.